Electrolytic recording electrode



July 31, 1945. H. c. RES$LER ELECTROLYTIC RECORDING ELECTRODE Filed Sept. 11, 1941 INVENTOR ffiyh flifiesaZer Y WWW ATTORNEY Patented July 31, 1945 ELECTROLYTIC RECORDING ELECTRODE Hugh 0. Ressler, West Brighton, N. Y., asslgnor to Faximile, Inc., New York, N. Y., a corporation of Delaware Application September 11, 1941, Serial No. 410,423

1 Claim.

changeable recording electrode.

Still another object is to provide improved means for adjusting the pressure at various points along the length of a flexible electrolytic recording electrode.

These and other objects will be evident from the detailed description of the invention given in connection with the various figures of the drawing.

In the drawing:

Fig. 1 shows a view of the side of one form of the present invention.

Fig. 2 shows a view of the edge of one form of the present invention.

Fig. 3 shows a cross-section of one of the adjusting means.

Fig. 4 shows a side view of one form of flexible electrode suitable to the present invention.

Fig. 5 shows a view useful in explaining the operation of the electrode of the present invention.

In electrolytic recording, such as facsimile, a sheet of sensitized paper is passed between a pair of electrodes carrying the modulated currents to be recorded. Commonly, the sheet is scanned line by line to produce a completed recording. A recording device suitable to the present invention is shown and described in Patent No.

2,202,855 entitled Facsimile recorder," issued on June 4, 1940, to John V. L. Hogan and Hugh C. Ressler. In the recording device shown in this patent, a sheet, properly sensitized, is passed 'between a linear electrode and a moving helical electrode. The intersection of the two electrodes produces a scanning point moving across the sheet. The sheet is moved along its length to provide the line by line scanning motion. Modulated current is passed between the two electrodes thru the sensitized paper at the recording point, The paper is sensitized, for instance, with an aromatic lake-forming material and is rendered electrolytically conductive with a salt, such as potassium'nitrate. The linear electrode is made at least partially of a lake-forming metal, such as iron and it forms an iron lake or high tlnctorial value upon passage of the recording current and oi a density substantially proportional to the ourrent supplied over the optimum recording range. While this is the preferred combnation, the flexible electrode of the present in ention may also be used in recording where the electrode is not consumed.

The present invention concerns a novel flexible linear electrode, mounting and adjusting means, and provisions for rapid replacement of the electrode element. As stated above, this electrode may be used in any suitable recorder, such as the one described in the above referred to patent. The electrode element itself is preferably in the form of a. long thin strip of metal. Typical di'- mensions -are 5.75 inches long by 0.25 inch wide by 0.012 inch thick, although considerable variation of these dimensions may be tolerated as long as, the electrode functions, as described below. i'lie electrode i mounted in a holder, so that it lies across the width of the recording sheet presenting its thickness dimension at the recording point and with its intermediate dimension substantially perpendicular to the recording sheet at the point of recording but preventing any appreciable motion along the sheet. The holder includes a plurality of springs for pressing the electrode against the recording sheet. The ends of the electrode element fit into slots in the holder preventing the electrode from dropping out of the holder when it is raised from the paper. A release device at one end of the holder permits the electrode element to be quickly removed and replaced by a new element.

Fig. 1 shows a complete electrode element 2 mounted in a holder 1. The electrode element 2 fits in a. slot 5 in holder i. Portions of holder i maybe cut away to form the projecting fingers 3 thereby reducing the friction to sliding motion of electrode 2 without appreciably decreasing the transverse support given. The electrode holder may be mounted on the recording machine by any convenient means as, for instance, by pins or screws passed thru mounting holes E. The end of electrode element 2 has a step i 0 cut at each end. This step it fits under fixed mounting piece 9 at one end and removable piece ii at the other end. This construction keeps the electrode elementjrom dropping out of the holder. In order to remove the element 2 for quick replacement. removable piece il may be released into the dotted position by unscrewing thumb nut it. In order to push electrode element 2 against the recording point, a number of plugs 6 backed by springs l and adjustable by means of screws 8 are provided. The plugs are wider than slot 5, so that they do not fall out when electrode ele- Fig. 2 shows an edge view of electrode elemen 2 and holder 1 with fingers 2, mounting holes 4, slot 8, mounting pieces I and l l and thumb nut l2.

Fig, 3 shows a cross-section along l'-l of Fig. 1 showing details of electrode 2, holder I, plug 0, spring I and adjusting screw 2. This figure also shows the relation of the recording sheet it moving in the direction of the arrow to the electrode element 2. Element 2 is permitted motion perpendicular to the surface of sheet II by motion of the electrode as a whole and by flexing or bending against springs 1. Element 2 is accurately held against motion or bending in the direction of motion of the paper it by the plurality of fingers 2. Aportion of the second or helical electrode II is also shown.

Fig. 4 shows a side view of electrode element 2 including the steps ll cut in its ends. This view also shows notches II and it useful in preventing warping of the electrode. Due to notches II one edge of the electrode is longer than the other aninch witha pressure less than that which would cut damp recording paper when pressed a ainst helix i3.

Since the recording speed will usually be of the order of 30 to 60 linear inches per second, it will be seen that the pressure must be light not to cut the paper. The fact that there is little inertia in the system, since only element 2 and plugs l are moved by the recording pressure, is a great advantage in preventing cutting otthe recording sheet. Actually, at any instance, only a fraction of this weight is in motion, since element 2 moves only a part at a time due to its flexing and bending. For example, the center of the electrode may be bent due to pressure of the helical electrode acting thru the paper by 0.01 of an inch, while the which may cause the electrode to warp due to temperature changes. Notches ii and II are useful in compensating the lengths of the 'two edges, thereby preventing the warping.

Fig. 5 shows an exaggerated view of the i'iexin'g or bending of element 2. When element 2 is removed from the paper it takes a substantially straight form, as shown dotted at '2. when pressed against a recording helix H (the paper between element 2 and helix (2 is omitted for aimplicity of illustration), the element 2 is flexed or bent into form 2. Thus, when helix i2 presses at the center of element 2, the center spring I is compressed slightly allowing bending of element 2, while its ends remain substantially in their original position. As helix i2 moves along the length of element 2, the point of maximum bend follows it from one end to the other. I

Electrode element 2 should be made of resilient material, such as steel. Element 2 should be flexible enough to flex or bend a few thousandths of ends at the same instant will move only about 0.002 of an inch perpendicular to the recording sheet or surface. Motion of the recording edge of the electrode element is restrained in a direction parallel to the recording sheet or surface at the point of marking. The maximum motion here will be of the order of 0.001 of an inch. It will be evident that this motion in the direction of motion of the sheet or surface should be less than the width of the recording line. The electrode may move a small amount along its length. ire. parallel to the sheet or surface across its direction of motion, without affecting f-he quality of the record. Maximum freedom perpendicular to the sheet or surface may be obtained by allowing motion also parallel to and across the direction of motion of the sheet or surface at the point of marking.

While only one embodiment of the present invention has been shown and described, many modifications will be apparent to those skilled in the art .wlthin the spirit and scope of the invention, as set forth in the appended claim.

a What is claimed is:

An electrode device for electrolytic recording including the combination of a thin, fiat strip of resilient metal, a slotted holder for supporting and confining said strip of metal in the direction of its least dimension and permitting sliding and flexing in the direction of its width dimension, and a plurality of springs spaced along the length of the holder for pressing the edge of said strip of metal against a recording surface, the length, thickness, width and material of said strip being determined to pennit flexing of said strip in the direction offlts width to tend to conform with irregularities in said recording surface.

' HUGH C. RESBLER. 

